1. Field of the Invention
The present invention relates to devices for preventing damage to electronic devices caused by electrostatic discharge (ESD), and in particular the invention relates to devices for preventing ESD-caused damage to portable electronic devices, such as cordless or cellular telephones and their bases or cradles, during their placement and removal from charging cradles, interface cables or other handling.
2. The Prior Art
Electronic devices are often susceptible to failure due to ESD. The risk of such damage is particularly great for devices that are directly handled by individuals on a regular basis, such as many portable electronic devices. Increasing the risk of ESD damage even further is the provision of a connector or electrical interface port on such portable electronic devices. For example, cordless and cellular telephones and/or their bases or cradles, are often susceptible to damage from ESD when the handset is placed on or removed from charging cradles or when connections are made or broken to data ports on the mobile electronic apparatus, or during other accidental or intentional contact. Protection from ESD becomes a larger concern when data ports are present, inasmuch as such mobile electronic apparatus typically contain circuitry that is particularly sensitive to damage, such as ASIC modules. In order to prevent damage from occurring, typical prior art mobile electronic apparatus, if protected at all, employ internal ESD protection circuitry, which can add to the size and/or cost of the circuitry package of the apparatus.
It would be desirable to provide a simplified, low cost device for protecting electronic devices, particularly those provided with charging and/or data ports, from damage caused by ESD.
It would also be desirable to provide a device for protection against damage to an electronic device caused by ESD, which does not otherwise interfere with the normal operation of the electronic device.
These and other desirable characteristics of the present invention will become apparent in view of the present specification and drawings.
The present invention is directed to an electrostatic discharge protection shield apparatus for an electrical connector for a corresponding electronic apparatus. The electrostatic discharge protection shield apparatus comprises a non-electrically conductive base for supporting the electrical connector; and an electrically conductive shield member, movably mounted on the base. The electrically conductive shield member is movable between a first position relative to the electrical connector, in which the electrically conductive shield member substantially protects the electrical connector from undesired contact, and a second position relative to the electrical connector, in which the electrically conductive shield member exposes the electrical connector for normal operation in contact with the corresponding electronic apparatus. A biasing mechanism prompts the electrically conductive shield member into its first position. The biasing structure is configured to resistively yield and permit movement of the electrically conductive shield member toward its second position, upon exertion of force on the electrically conductive shield member in excess of a predetermined amount.
Preferably, the electrical connector has an axis, and the electrically conductive shield member is configured to move parallel to the axis of the electrical connector.
In a preferred embodiment of the invention, the electrical connector has a dimension in a direction parallel to its axis which is greater than a corresponding dimension of the electrically conductive shield member extending in a direction parallel to the axis of the electrical connector. The electrostatic discharge protection shield apparatus would further comprise an aperture, disposed in the electrically conductive shield member, and having an axis parallel to the axis of the electrical connector, through which the electrical connector is configured to pass, so that when the electrically conductive shield member is in its first position, it surrounds an end of the electrical connector where electrical contacts are situated, and when the electrically conductive shield member is in its second position, the end of the electrical connector where electrical contacts are situated is exposed.
Preferably, the electrostatic discharge protection shield apparatus further comprises at least one guide member, operably associated with the base and extending parallel to the axis of the electrical connector; and at least one guide member receiving aperture disposed in the electrically conductive shield member, for constraining the movement of the electrically conductive shield member to be in a direction parallel to the axis of the electrical connector.
In a preferred embodiment of the invention, the biasing mechanism comprises a coil spring, under compression, disposed between the non-electrically conductive base and the electrically conductive shield member, so that the coil spring tends to push the electrically conductive shield member away from the non-electrically conductive base. Structure operably associated with the base limits the distance away from the non-electrically conductive base that the biasing mechanism can push the electrically conductive shield.
Preferably, the electrostatic discharge protection shield apparatus further comprises an electrical ground, operably configured to remain in continuous contact with the electrically conductive shield member, throughout the movement of the electrically conductive shield member between its first and second positions, for permitting conduction of electrostatic discharges away from the electrical connector.
In a preferred embodiment of the invention, the electrical ground comprises the biasing mechanism being fabricated at least in part from electrically conductive material.